ROCKVILLE, MD. — Chronic back pain is an enormously heterogeneous and common disorder that might better be examined in observational “Framingham-like studies” than in randomized, controlled clinical trials.
The recommendation was proposed by several presenters at the workshop, sponsored by the National Center for Complementary and Alternative Medicine (NCCAM), a division of the National Institutes of Health.
With seven thematic panels and 23 speakers, the meeting included lively discussions about optimal approaches for studying a problem that affects one in four adults and costs the health care system billions of dollars annually, and for which research thus far has not yielded the kinds of interventions that can help the majority of affected patients.
“I think this is the right time to be talking about this problem. The NIH has certainly been urged by our leader, Dr. Francis Collins, to worry about research of relevance to health policy, and I can't think of a single issue that has as much resonance or potential implications for health policy as this one,” NCCAM director Dr. Josephine Briggs said.
Dr. Briggs, who was originally trained in internal medicine and nephrology, also noted, “This is not my area, but as I've learned more about back pain over the last year, I have been absolutely blown away by the magnitude of this problem and the enormous clinical difficulties in bringing relief to most patients suffering from chronic back pain…. This is totally pervasive, a huge driver of health costs.”
There was agreement among participants that chronic back pain is not simply a multifaceted biological problem, but also a psychosocial one. As such, there is little correlation between physical findings on imaging or other studies and the degree to which a patient perceives pain or experiences functional impairment. Participants also generally agreed that current treatments, including opioids and surgical approaches, are ineffective in many patients and have been associated with harm as well.
Several speakers pointed out that the extensive heterogeneity in causes, presentations, and functional impact of chronic back pain has made it difficult to define “case-ness,” which in turn makes it impossible to compare studies on the problem and determine the extent to which results from any given study can be extrapolated to another.
Indeed, even the most commonly used definition of “chronic”—pain lasting longer than 3 or 6 months—is limiting in that it doesn't account for other parameters such as pain intensity, associated psychological dysfunction, or degree of functional impairment, noted Michael Von Korff, Sc.D., senior investigator at Group Health Research Institute, Seattle.
He described an alternative “prognostic risk score” that would not only classify patients with back pain but would also help to determine their probability of future clinically significant back pain. The score, derived from a study of 1,213 primary care back pain patients, utilizes measurements of degrees of pain intensity, interference with activities, persistence, number of pain sites, and depression to define risk levels corresponding to a 50% and an 80% probability of future clinically significant pain (Pain 2005;117:304–13).
Such an “empirically grounded” approach, he said, could help distinguish patients at low risk who could be managed conservatively from those at greater risk for whom intervention could be initiated early, rather than waiting for the passage of time until they meet the “chronic” criteria. Moreover, “it avoids labeling patients as hopeless, with immutable back pain, when change for the better is always possible and often likely.”
Indeed, noted Dr. Gary Franklin, a research professor in environmental and occupational health sciences at the University of Washington, Seattle, the Food and Drug Administration uses only pain as a primary outcome measure for drug trials, with function and quality of life as secondary outcomes. “The FDA needs to consider using a composite measure,” he commented.
Several speakers questioned whether the randomized clinical trial, widely considered the “gold standard” type of study for the efficacy of drugs, is really the best type of trial to examine aspects of such a heterogeneous problem as chronic back pain, and whether longitudinal observational “Framingham-like” study might be more appropriate to determine what happens to patients with chronic back pain over time.
In an interview, workshop cochair Dr. Partap Khalsa, program officer of the division of intramural research at NCCAM, noted that the best clinical guidelines currently available for managing chronic low back pain are those developed jointly by the American College of Physicians and the American Pain Society. They advise clinicians to conduct a focused history and physical to help determine etiology, and only perform diagnostic imaging in selected patients with severe or progressive neurologic deficits or in whom serious underlying conditions are suspected based on the history and physical exam (Ann. Intern. Med. 2007;147:478–91).